I think by the time you have had the car shipped and had all the stuff done to conform it to uk standards, converted it to right hand drive and registerred it there is not realy a great saving for the pain in the ass this sounds like also I think the insurance may be a problem
I don't think its gonna be worth it if you're looking to save money but if you want to bring in a hummer or a corvette or something you can't buy in the UK and keep it left hand drive there are places that can help you or where you can buy already done cars like:
http://www.newport-imports.com/